I was noticing the after_header hook works correctly on blog post types, it is placed right after the menu before the content and featured image. But if a featured image is enabled on a page the after header hook is after the featured image. Is there a way to place something before the featured image but after the header on pages?
you can try reducing the priority (default is 10) on the hook, a lower number will hook it earlier.
But it shouldn’t come after an in post featured image. Can you link us to a page where that is happening.